Indicator for electric fuses



Nov. 19, 1935. v s BAKER 2,021,473

INDICATOR FOR ELECTRIC FUSES Filed Sept. 22,. 1932 55 61 I I I Z 0 52 INVENTOR 53 STANLEYBAKER ATTORNEY reeeivethe fuse of the cartridge" 4b :9: electric hises; sauna; '2

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v September :2, 1932; Serial No. 034,325

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' of a simple. compact'and eitectiv'e unit embody- 1 10 n! h fusible and the signal element.

[ 'A'nother object, or the invention resides in the provisionofauhltoithis naturewhichmaybe as a whole from the circuitwith shock. i'orthe pur is pose oi replacement of a blown fuse-all live I iongitudinallyalong the bottom to form a recess A still further ohiect of the invention resides. in (construction which prevents contact with n all sharp edges and particularly contact with fuse holder: adapted to In out theinvention, a insuuranged to carry an electric v, lation's'member is t I 25 time or cut-out. an electric lamp' and a rela-.

' iv b'mzh the l m and r si t n being'in sales with aachother in shunt,

'with the fuse or cut-out. The foregoing elements constitute a complete vunit. which may the fuse element andof which condition visible notieeis given thmllih the illumination Yloi. the lamp its energization when 35 the fuse element tails.

" The nature of theinverit ionQhoweveflwill best with vertical section illustrating a further modification; and Fig; .9 illustrates in elevation a still further modification. g V

Referring to the drawing, more particularly Figs; 1 to 8, the indicator device is shown as 5 constructed of two halves II and ii of insulating material, the upper portion being provided with respective digital recesses l2 and it adapted to register when the halves are locked together and to aflord a handle or gripping portion for use 10 in installing the fus'e'in the line'or withdrawing it therefrom for; replacement of its-fusible eleinent when thesame' is ruptured; y j" The halves l'nayconveniently be "held together by bolts lliand nuts It, and are both undercut It into which is adapted to be placed and securelyheld the fuse element I! which in the particular embodiment is 'of the cartridge type.

a convenient means for retaining the fuse element in position in the holder, constituted by the halves II and), the latter may be provid'ed (with like. positioned slots 20 having an inclined entranceportion and a horizontal holding portion. I 'lhese arejadapted to receive '25 f correspondingpins; II which prolec't in opposite directions nomjs curved supp rt member 22 designed to lit underthe fuse I1 and retain the same in position within the it when the pins are in the horizontal portion of the grooves 20. l a l The fuse ele'mentis' provided with end termi- 11318 2! and 24 designed to fit, when the fuse is "putinto services, suitable .upsanding spring clips or the like it and 2l,,respectively. and as is well understood. Contact brushes 2! and It, mo c i lv,.'fensase the upper surfaces of the terminalsifl'and It and are fixedly in suitable manner. within one oi the halves,

as the half II; This latter half, also, is provided 40 "with a suitable socket ll, preferably threaded, to jreceive' anelect'rlc'lamp II, the bottoms-of the a recesses II and It being further cut away to accommodate thes c et and which latlter transversely over the halves.

lloreoverga "relatively high resistance element 32 is imbedded in the insulation material of, for example, the half it, and is included in seria with the said lamp ti: and both are connected in shunt with the respective contact brushes 2! and It to place said lamp and resistance in shunt with the fuse element.

Thus, so long as the fuse element remains intact, only a minute current will flow through the ""shuntcircuitincludingthelampandresistanee ts r but if the fuse should fail, the lamp 3| will be illuminated to give visible notice of such failure, so that replacement may be made.

In effecting a replacement, the entire unit is to be withdrawn by disconnecting the fuse portion, or rather the terminals 23 and 24 thereof, from the clips 25 and 26 in grasping the indicator devices at the digital recesses I2, i3 and pulling it away from the said clips. This will disconnect all live parts so that the device may be handled with entire safety from electrical shock, and the fuse element replaced apart from the live clips. This replacement is effected by first sliding the pins 2i downwardly through the slots 2' to release the fuse element N, then replacing the blown fuse with an effective one, restoring the holding member 22 through re-engagement of the pins in the horizontal portion of the slots, and finally snapping the terminals into their clips.

In Figs. 4 to 6, a somewhat different arrangement for a cartridge type fuse is set forth, the same being constituted of a single block 35 of insulating material. This block is recessed or undercut along the bottom throughout its entire length to provide a longitudinal opening or groove 36 therethrough. The upper portion of the block is provided with a socket 31 to receive an electric lamp 38 designed to project longitudinally over the top of the block, and a resistance 39 in series therewith is imbedded in the upper portion of said block. The lamp and resistance, in turn, are adapted to be connected to the fuse element 40, or rather the end terminals 4i and 42 thereof through brush elements 43 and 44 carried at the bottom of the recess 36 and adapted to contact with said terminals when a fuse is positioned in the block. The lamp and resistance will thus be connected in shunt with the said fuse element.

In order to retain said fuse element 40 in position within the block, as aforesaid, a supporting and guiding strap or plate 45 is located transversely of the same over the bottom of the opening 36, the side walls of the block being recessed as at 46 for this purpose; and the plate may be securely held, while the device is in use, to said block 35 as by means of a U-shaped handle member 41 the legs of which pass through the body 35 and plate 45 and may be secured to the latter by nuts 48 and 49. The exposed lower portion of the end terminals 4i and 42 are designed to fit within suitable spring clips or the like (not shown), as in the previously described embodiment.

When it is desired to replace the fuse element 40, the entire unit is first lifted out of contact with the clips of the line, and the fuse element is then forced longitudinally out through the opening 36, as by pushing inwardly at one end and then grasping the protruding end. Simi larly, an effective fuse is installed by inserting the same at the one end of the longitudinal opening and pushing it therethrough until its terminal elements 4i and 42 register with the brushes 43 and 44, respectively, to re-establish the contact with the shunt circuit including the lamp and resistance. The unit may then be restored to its position in the line in manipulating the same by means of the handle 41.

In Figs. 7 and 8 a screw plug type of fuse is disclosed, the unit being designed to be discarded s as a whole when the fuse is blown. In this embodiment, an insulating body ll is provided with the downwardly threaded extension ll surrounded by correspondingly threaded terminal I! for insertion in the usual screw socket (not shown) 10 of a line. A further and axial terminal 53 is provided in the extension at its outer end, as in the usual form of this type of fuse. A fuse element 54 is included between the said terminals, which, if blown, will interrupt the line circuit. 15

In addition, and in accordance with the invention, there is provided in the head or body portion 40 a screw socket 55 for an electric lamp l6, and a relatively high resistance element 81 is embedded in the extension 5i the lamp and re- 2 sistance being connected in shunt with the fuse terminals 52 and 53, respectively, whereby, when the fuse element 54 fails, the current will be diverted to the lamp in suiilcicnt amount to illuminate the same. The plug is then to be unscrewed 5 from its line socket and replaced by aneifective fuse plug of the same nature; or if of the type in which a plurality of fuse elements is provided a new fuse is positioned.

Furthermore, the fuse element may be in the 3 nature of the well-known fuse plug, as the member 33, Fig. 9, the remainder of the indicator device then serving as an adapter for insertion into the line and internally threaded as at H to receive the said plug which is screwed therein. In 35 making a renewal either the plug alone is withdrawn or, preferably, the adapter with plug is removed and the defective fuse plug then unscrewed therefrom and replaced by a new one.

I claim: w

l. A screw plug fuse, comprising a head portion provided with a cavity for a fuse element and with a downward extension having a threaded terminal and an axial terminal for contact with a screw socket of the line, the fuse being adapted for connection between said terminals, and a lamp mounted in the wall surrounding the fuse cavity with its axis substantially parallel to the longitudinal axis of the plug and the lamp projecting beyond the end of the head portion 0 opposite its downward extension, said lamp being connected in shunt with the said terminals.

2. A screw plug fuse, comprising a head portion provided with a cavity threaded to receive a screw plug fusible element and with a down- 5 ward extension having a threaded terminal and an axial terminal for contact with a screw socket of the line, the fusible element being adapted for connection between said terminals, and a lamp mounted in the wall surrounding the fuse cavity with its axis substantially parallel to the longitudinal axis of the plug and the lamp proiecting beyond the end of the head portion opposite its downward extension, said lamp being connected in shunt with the said terminals. g.

STANLEY BAKER. 

